Worry about dizziness during pregnancy if it is severe, persistent, or accompanied by other concerning symptoms such as fainting, shortness of breath, chest pain, irregular heartbeat, blurred vision, vaginal bleeding, abdominal pain, or if you cannot lie flat without feeling short of breath. Fainting spells during pregnancy, especially in the first trimester, require immediate medical attention as they may increase the risk of pregnancy complications or signal underlying health issues like heart conditions or preeclampsia. Dizziness is common in pregnancy, particularly in the first trimester due to hormonal changes causing low blood pressure and lower blood sugar. It may also occur in later trimesters due to pressure from the growing uterus on blood vessels or conditions like preeclampsia. Preventative measures include staying hydrated, standing up slowly, eating regularly, and avoiding lying flat on your back in the second and third trimesters. However, if dizziness is associated with more severe symptoms, medical evaluation is necessary.